This invention relates to decorative sheets which are utilized in the step of finishing the surfaces of furniture and like articles and to a method for producing the same. More particularly, the present invention relates to a decorative sheet having an adhesive layer which can be adhered to a base material for a decorative plate only by hot pressing, that is, which can exhibit adhesiveness by hot pressing on the back surface, and to a method for obtaining the decorative sheet.
As a method for obtaining a decorative plate which exhibits excellent effect in design characteristics by causing a decorative sheet to adhere to a base material for a decorative plate, there are:
1) a method in which, during adhesion of a decorative sheet to a base material for a decorative plate, an adhesive is applied as a coating on the back surface of the decorative sheet or on the surface of the base material for the decorative plate, and subsequently heat and pressure are applied to obtain a decorative plate, and
2) a method in which a resin layer extruded into a film by an extruder is laminated on the back surface of a decorative sheet to obtain a decorative sheet having an adhesive layer on the back surface, and then this is adhered under heat and pressure onto a base plate for a decorative plate to obtain a decorative plate.
In the method for producing a decorative plate comprising a laminated product of a decorative sheet and a base material for a decorative plate of the prior art as described above, the method 1) requires a coating machine for an adhesive during production of the decorative plate, and therefore the production steps will become large in scale and time, because curing of the adhesive will be required during production of the decorative plate, whereby the production efficiency of the decorative plate will be poor. Furthermore, wrinkles, swelling, etc. caused by defective adhesion on the decorative plate obtained occur and give rise to defects such as poor appearance of the decorative plate.
On the other hand, the decorative plate obtained by the method 2) has an adhesive layer formed on the back surface of the decorative sheet which is obtained by causing a resin layer once formed into a film to adhere to the back surface of the decorative sheet and therefore has the drawback of weak adhesive force between the decorative sheet and the adhesive layer. Another drawback is that since the adhesive layer on the back surface of the decorative sheet is constituted of a resin having extrusion adaptability, that is, a resin having a high melting temperature, a high temperature is required during bonding of the decorative sheet onto the base material for a decorative plate by utilizing the hot-melting fusibility possessed by the adhesive layer through the resin, which is uneconomical and also entails a cumbersome temperature management. Also, since the adhesive layer on the back surface of the decorative sheet comprises a resin once rendered into a film laminated on the decorative sheet, the adhesive layer cannot be made thin, whereby a decorative sheet having an adhesive layer with desired physical properties cannot be obtained.